One prior art heat sink design is a U-shaped heat sink stamped from sheet metal. The U-shaped heat sink is fastened to a component requiring heat dissipation. The component is typically soldered to a printed circuit board such as a motherboard. For some applications, the heat sink form factor may be small enough so that its mass can be supported by the legs of the component. The size of the heat sink, however, tends to increase as the thermal dissipation requirements increase. The legs of the component may not be sufficiently sturdy to support the larger heat sink.
The stamped heat sink can be fastened to the motherboard in order to provide support. The stamped heat sink can be manufactured with tabs that are inserted through the motherboard and then twisted or bent to hold the heat sink in place. Alternatively, another coupling mechanism such as spring clips can be soldered to the motherboard. The heat sink is then pushed onto the spring clips.
One disadvantage of the use of tabs is that the additional bending or twisting step is required when fastening the heat sink to the motherboard. Similarly, the additional steps may be required at the time of fastening the heat sink to the motherboard if spring clips are used.
Some applications require heavier duty heat sinks that are typically manufactured using an extrusion process rather than the stamping process. Due to limitations in the extrusion process, the extruded heat sink typically cannot be extruded with mounting pins or tabs. Regardless, additional manufacturing steps may be required at the time of fastening the heat sink to the motherboard even if mounting tabs or spring clips can be used with the extruded design.
Another disadvantage of prior art stamped or extruded heat sinks is that the component being cooled is typically fastened to the heat sink using a screw and a nut. This requires aligning holes in the component and the heat sink as well as the screw and the nut during assembly. When tightening the screw and nut, the component tends to rotate with respect to the heat sink. Unless the rotation is insubstantial, the component and the heat sink may need to be re-adjusted in order that both may be properly seated on the motherboard.